(ORDO NEWS) — Astronomers have been surprised to discover the origin of the closest source to Earth of mysterious flashes in the sky called fast radio bursts.
Precision measurements made with radio telescopes have shown that these flares are born among old stars, and are formed in accordance with a very unusual mechanism. The source of these flares, located in the spiral galaxy M81, is the closest known source of this type to Earth.
Fast radio bursts are sudden, extremely short bursts of radiation in outer space. Astronomers have not been able to understand the nature of these flares since their discovery in 2007. Until now, these events have only been observed in the radio spectrum.
Each such flash lasts only thousandths of a second. However, during this time, as much energy is transferred as our Sun radiates in a day.
Every day, hundreds of fast radio bursts are observed in the sky, in all directions. Most of the sources of these flashes lie at gigantic distances from the Earth, in galaxies that are billions of light years away from our planet.
In two new scientific papers, an international team of astronomers led by Franz Kirsten from Chalmers University of Technology, Sweden, have made precision measurements of the parameters of a repetitive fast radio burst discovered in January 2020 in the direction of the constellation Ursa Major.
As a result of the analysis, scientists were able to establish that the origin of the source under study is the galaxy Messier 81 (M81), located at a distance of about 12 million light-years from us. This makes the source under study the closest source of fast radio bursts known to scientists to us.
Moreover, as it turned out, this fast radio burst comes from the periphery of the M81 galaxy, from a globular cluster of stars.
This result surprised scientists, since sources of fast radio flares are usually found in neighborhoods richer in young, massive stars. In clusters of young stars, stellar explosions often occur, leaving behind magnetized remnants of stars called magnetars, which are often associated with fast radio bursts.
Therefore, as a working hypothesis, Kristen and his team suggested that the source of the observed radio flares is an unusual magnetar, formed as a result of accretion of material from one white dwarf to another.
White dwarfs are the remnants of low-mass stars, and the transformation of two white dwarfs into an exotic magneter can occur under conditions of a close globular cluster when two such objects approach each other before the start of effective gravitational interaction with mass transfer from one white dwarf to another.
As a result of accretion of mass, the white dwarf turns into a superdense neutron star with a powerful magnetic field, called a magnetar, which gives rise to fast radio flares, Kristen and his team believe.
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